Electrical circuits of dwellings, houses or office buildings, for example, with one load or several loads, are typically protected from sustained overcurrents and short-circuit currents by a protective device in the form of a fuse or a circuit breaker. Usually several electrical circuits are then operated in parallel and supplied with electricity from at least one power line, wherein the protective devices are disposed between the electrical circuits and the power line and together form a protective system. After a fuse has been blown or a circuit breaker has been tripped, typically the respective protective devices have to be replaced or reset, which is laborious and causes costs. Furthermore, with conventional fuses and circuit breakers, the power consumption cannot be reproduced or controlled by individual electrical circuits. This is of particular interest precisely in times of rising electricity prices and fluctuating availability of electricity in the power line.
GB 2 450 426 A teaches switching relays, which are connected to fuses or circuit breakers and which can be opened and closed by means of a remote controller in order to open or close electrical circuits. Power-measuring units are able to measure the power consumption in the electrical circuits protected by fuses or circuit breakers and transmit it to the remote controller, so that a user of the remote controller can decide on the basis of the power consumption of the respective electrical circuits whether an electrical circuit should be disconnected or remain closed. The system disclosed by GB 2 450 426 A permits protection of the electrical circuits against sustained overcurrents and short-circuit currents as has been usual heretofore by its fuses or circuit breakers, and so they must still be replaced or reset if they are blown or tripped. The system disclosed by GB 2 450 426 A involves complex equipment, necessitates additional overall space, especially in the region of the fuses or circuit breakers and to only a very limited extent permits control of the protective system comprising several fuses or circuit breakers and of the power consumption in individual electrical circuits.